<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }

        canvas {
            display: block;
        }

    </style>
</head>
<body onload="draw();">

</body>
<script src="http://www.yanhuangxueyuan.com/versions/threejsR92/build/three.js"></script>
<script src="js/controls/OrbitControls.js"></script>
<script src="js/libs/stats.min.js"></script>
<script src="js/libs/dat.gui.min.js"></script>
<script src="js/lights/RectAreaLightUniformsLib.js"></script>

<script>
    var renderer;
    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias: true});
        renderer.setSize(window.innerWidth, window.innerHeight);
        //告诉渲染器需要阴影效果
        renderer.shadowMap.enabled = true;
        renderer.shadowMap.type = THREE.PCFSoftShadowMap; // 默认的是，没有设置的这个清晰 THREE.PCFShadowMap
        //renderer.gammaInput = true;
        //renderer.gammaOutput = true;
        document.body.appendChild(renderer.domElement);
    }

    var camera;
    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
        camera.position.set(0, 40, 100);
        camera.lookAt(new THREE.Vector3(0, 0, 0));
    }

    var scene;
    function initScene() {
        scene = new THREE.Scene();
    }

    var rectLight,rectLightHelper;
    function initLight() {

        var ambientLight = new THREE.AmbientLight(0x111111);
        scene.add(ambientLight);

        rectLight = new THREE.RectAreaLight(0xffffff, 500, 10, 10);
        rectLight.position.set(5, 10, -20);

        scene.add(rectLight);
        // TODO: ensure RectAreaLight handles target param correctly

        rectLightHelper = new THREE.RectAreaLightHelper(rectLight);
        scene.add(rectLightHelper);
    }

    var cube,plane;
    function initModel() {

        //辅助工具
        var helper = new THREE.AxisHelper(10);
        scene.add(helper);

        //球体
        var sphereGeometry = new THREE.SphereGeometry(10,30,30);
        var sphereMaterial = new THREE.MeshStandardMaterial({color:0xff00ff});
        var sphere = new THREE.Mesh(sphereGeometry,sphereMaterial);
        sphere.position.set(-20,20,0);

        sphere.castShadow = true;

        scene.add(sphere);

        //立方体
        var cubeGeometry = new THREE.CubeGeometry(10,10,10);

        var cubeMaterial = new THREE.MeshLambertMaterial({color: 0x00ffff});

        cube = new THREE.Mesh(cubeGeometry, cubeMaterial);
        cube.position.x = 30;
        cube.position.y = 5;
        cube.position.z = -5;

        //告诉立方体需要投射阴影
        cube.castShadow = true;

        scene.add(cube);

        //底部平面
        var planeGeometry = new THREE.PlaneGeometry(5000, 5000, 20, 20);
        var planeMaterial = new THREE.MeshStandardMaterial({color: 0xaaaaaa});

        plane = new THREE.Mesh(planeGeometry, planeMaterial);
        plane.rotation.x = -0.5 * Math.PI;
        plane.position.y = -0;

        //告诉底部平面需要接收阴影
        plane.receiveShadow = true;

        scene.add(plane);

    }

    //初始化性能插件
    var stats;
    function initStats() {
        stats = new Stats();
        document.body.appendChild(stats.dom);
    }

    //用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
    var controls;
    function initControls() {

        controls = new THREE.OrbitControls(camera, renderer.domElement);
        // 如果使用animate方法时，将此函数删除
        //controls.addEventListener( 'change', render );
        // 使动画循环使用时阻尼或自转 意思是否有惯性
        controls.enableDamping = true;
        //动态阻尼系数 就是鼠标拖拽旋转灵敏度
        //controls.dampingFactor = 0.25;
        //是否可以缩放
        controls.enableZoom = true;
        //是否自动旋转
        controls.autoRotate = false;
        //设置相机距离原点的最远距离
        controls.minDistance = 50;
        //设置相机距离原点的最远距离
        controls.maxDistance = 200;
        //是否开启右键拖拽
        controls.enablePan = true;
        //设置从上面到下面的可旋转角度
        controls.maxPolarAngle = Math.PI*4.5/10;
        //设置从下面到上面的可旋转角度
        //controls.minPolarAngle = Math.PI/2;
    }


    //初始化dat.GUI简化试验流程
    var param;
    function initGui() {
        //声明一个保存需求修改的相关数据的对象
        param = {
            motion: true,
            width: rectLight.width,
            height: rectLight.height,
            color: rectLight.color.getHex(),
            intensity: rectLight.intensity
        };

        var datGui = new dat.GUI();
        //将设置属性添加到gui当中，gui.add(对象，属性，最小值，最大值）

        //var lightFolder = gui.addFolder('Light');

        datGui.add(param, 'width', 0.1, 100).onChange(function (val) {

            rectLight.width = val;

        });

        datGui.add(param, 'height', 0.1, 100).onChange(function (val) {

            rectLight.height = val;

        });

        datGui.addColor(param, 'color').onChange(function (val) {

            rectLight.color.setHex(val);

        });

        datGui.add(param, 'intensity', 0.0, 1000).onChange(function (val) {

            rectLight.intensity = val;

        });

        datGui.open();

    }

    function render() {
        rectLightHelper.update();
        renderer.render(scene, camera);
    }

    //窗口变动触发的函数
    function onWindowResize() {

        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        render();
        renderer.setSize(window.innerWidth, window.innerHeight);

    }

    function animate() {
        //更新控制器
        render();

        //更新性能插件
        stats.update();

        controls.update();

        requestAnimationFrame(animate);
    }

    function draw() {
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
        initStats();
        initGui();

        animate();
        window.onresize = onWindowResize;
    }
</script>
</html>